<?php
/**
 * log4php is a PHP port of the log4j java logging package.
 * 
 * <p>This framework is based on log4j (see {@link http://jakarta.apache.org/log4j log4j} for details).</p>
 * <p>Design, strategies and part of the methods documentation are developed by log4j team 
 * (Ceki Gülcü as log4j project founder and 
 * {@link http://jakarta.apache.org/log4j/docs/contributors.html contributors}).</p>
 *
 * <p>PHP port, extensions and modifications by VxR. All rights reserved.<br>
 * For more information, please see {@link http://www.vxr.it/log4php/}.</p>
 *
 * <p>This software is published under the terms of the LGPL License
 * a copy of which has been included with this distribution in the LICENSE file.</p>
 * 
 * @package log4php
 * @subpackage spi
 */

/**
 * @ignore 
 */
if (!defined('LOG4PHP_DIR')) define('LOG4PHP_DIR', dirname(__FILE__) . '/..');
 
/**
 * The log event must be logged immediately without consulting with
 * the remaining filters, if any, in the chain.  
 */
define('LOG4PHP_LOGGER_FILTER_ACCEPT',  1);

/**
 * This filter is neutral with respect to the log event. The
 * remaining filters, if any, should be consulted for a final decision.
 */
define('LOG4PHP_LOGGER_FILTER_NEUTRAL', 0);

/**
 * The log event must be dropped immediately without consulting
 *  with the remaining filters, if any, in the chain.  
 */
define('LOG4PHP_LOGGER_FILTER_DENY',    -1);

/**
 * Users should extend this class to implement customized logging
 * event filtering. Note that {@link LoggerCategory} and {@link LoggerAppenderSkeleton}, 
 * the parent class of all standard
 * appenders, have built-in filtering rules. It is suggested that you
 * first use and understand the built-in rules before rushing to write
 * your own custom filters.
 * 
 * <p>This abstract class assumes and also imposes that filters be
 * organized in a linear chain. The {@link #decide
 * decide(LoggerLoggingEvent)} method of each filter is called sequentially,
 * in the order of their addition to the chain.
 * 
 * <p>The {@link decide()} method must return one
 * of the integer constants {@link LOG4PHP_LOG4PHP_LOGGER_FILTER_DENY}, 
 * {@link LOG4PHP_LOGGER_FILTER_NEUTRAL} or {@link LOG4PHP_LOGGER_FILTER_ACCEPT}.
 * 
 * <p>If the value {@link LOG4PHP_LOGGER_FILTER_DENY} is returned, then the log event is
 * dropped immediately without consulting with the remaining
 * filters. 
 * 
 * <p>If the value {@link LOG4PHP_LOGGER_FILTER_NEUTRAL} is returned, then the next filter
 * in the chain is consulted. If there are no more filters in the
 * chain, then the log event is logged. Thus, in the presence of no
 * filters, the default behaviour is to log all logging events.
 * 
 * <p>If the value {@link LOG4PHP_LOGGER_FILTER_ACCEPT} is returned, then the log
 * event is logged without consulting the remaining filters. 
 * 
 * <p>The philosophy of log4php filters is largely inspired from the
 * Linux ipchains. 
 * 
 * @author VxR <vxr@vxr.it>
 * @version $Revision: 1.1 $
 * @package log4php
 * @subpackage spi
 */
class LoggerFilter {

    /**
     * @var LoggerFilter Points to the next {@link LoggerFilter} in the filter chain.
     */
    var $next;

    /**
     * Usually filters options become active when set. We provide a
     * default do-nothing implementation for convenience.
    */
    function activateOptions()
    {
        return;
    }

    /**   
     * Decide what to do.  
     * <p>If the decision is {@link LOG4PHP_LOGGER_FILTER_DENY}, then the event will be
     * dropped. If the decision is {@link LOG4PHP_LOGGER_FILTER_NEUTRAL}, then the next
     * filter, if any, will be invoked. If the decision is {@link LOG4PHP_LOGGER_FILTER_ACCEPT} then
     * the event will be logged without consulting with other filters in
     * the chain.
     *
     * @param LoggerLoggingEvent $event The {@link LoggerLoggingEvent} to decide upon.
     * @return integer {@link LOG4PHP_LOGGER_FILTER_NEUTRAL} or {@link LOG4PHP_LOGGER_FILTER_DENY}|{@link LOG4PHP_LOGGER_FILTER_ACCEPT}
     */
    function decide($event)
    {
        return LOG4PHP_LOGGER_FILTER_NEUTRAL;
    }

}
?>